Patent GB-652668-A (GB)
Title: Improvements in or relating to processes of preparing vulcanization accelerators, the vulcanization accelerators resulting from said processes and processes of vulcanizin g rubber
IPC: C08K5/00
Filed: 1948-07-09
Abstract: Synthetic rubbers are vulcanized by heating in the presence of a composition prepared by treating with a base, the heat fusion product of a 2,21-dithio bis thiazole accelerator and sulphur.  The preferred thiazole is 2,21-dithio bis benzthiazole, others specified are 2,21-dithio bis 4,5-dimethyl thiazole, 2,21-dithio bis 4-ethyl thiazole, 2,21-dithio bis 4-phenylbenzothiazole, 2,21-dithio bis 6-phenyl benzthiazole and 2,21-dithio bis chlorobenzthiazole.  The base, which may be added prior to, during, or after the fusion of the thiazole may consist of an alkali or alkaline earth metal hydroxide, ammonia, cyclohexylamine, benzylamine, piperidine, ethylamine, diethylamine, methyl amine, dimethyl amine, morpholine or methyl cyclohexylamine.  The amount of base is normally 0.1 to 1.0 per cent of the weight of the thiazole and sulphur fusion product, which should contain more than 50 per cent of sulphur.  The synthetic rubber may be a butadiene-1,3 polymer, or a copolymer of butadiene with styrene or acrylonitrile.  In examples, the effect of various of the above compositions was indicated on mixes consisting of GR-S, carbon black, zinc oxide, and sulphur, with the optional addition of stearic acid, hydrocarbons, and N-cyclohexyl 2-benzthiazole sulphenamide.  In addition, basic activating accelerators such as diphenyl guanidine, di-o-tolyl guanidine, thiocarbanilide, hexamethylene tetramine, paraphenylene diamine, anhydro formaldehyde aniline, diphenyl guanidine phthalate, triphenyl guanidine, butyl aldehyde aniline, dibutyl amine oleate and dicyclohexylamine oleate may also be added.ALSO:A rubber vulcanizing accelerator is made by treating the composite heat fusion product of a 2,21-dithio bis thiazole accelerator and sulphur with a base.  The preferred thiazole is 2,21-dithio bis benzothiazole, other thiazoles specified are 2,21-dithio bis 4,5-dimethyl thiazole, 2,21-dithio bis 4-ethyl thiazole, 2,21-dithio bis 4-phenylbenzothiazole, 2,21-dithio bis 6-phenylbenzothiazole and 2,21-dithio bis chlorobenzthiazole.  The base which may be added prior to, during, or after the fusion of the thiazole may consist of an alkali or alkaline earth metal hydroxide, ammonia, cyclohexylamine, benzylamine, piperidine, ethyl amine, diethylamine, methylamine, dimethylamine, morpholine or methyl cyclohexylamine.  The amount of base is normally 0.1 to 1.0 per cent of the weight of the sulphide and sulphur fusion product which should contain more than 50 per cent sulphur.  Typical vulcanization mixes are described in Group V.ALSO:Natural and synthetic rubbers are vulcanized by heating in the presence of a composition prepared by treating with a base the heat fusion product of a 2,21-dithio-bis-thiazole accelerator and sulphur.  The preferred thiazole is 2,21-dithio-bis-benzothiazole, other thiazoles specified are 2,21-dithio-bis-4,5-dimethyl thiazole, 2,21-dithio-bis-4-ethyl thiazole, 2,21-dithio-bis-4-phenylbenzothiazole, 2,21-dithio-bis-6-phenyl-benzothiazole and 2,21-dithio-bis-chlorobenzthiazole.  The base, which may be added prior to, during or after the fusion of the thiazole may consist of an alkali or alkaline earth metal hydroxide, ammonia, cyclohexylamine, benzylamine, piperidine, ethylamine, diethylamine, methylamine, dimethylamine, morpholine, or methyl cyclohexylamine. The amount of base is normally 0.1 to 1.0 per cent of the weight of the thiazole and sulphur fusion product which should contain more than 50 per cent of sulphur.  The rubbers may be indiarubber, reclaimed rubber, balata, guttapercha, butadiene-1,3 polymer and copolymers of butadiene with styrene or acrylonitrile.  In examples, the effect of various of the above compositions was indicated on mixes consisting of smoked sheet rubber or GR-S rubber, carbon black, zinc oxide and sulphur with the optional addition of stearic acid, hydrocarbons and N-cyclohexyl 2 - benzothiazole sulphenamide.  In addition basic activating accelerators such as diphenyl guanidine, di-o-tolyl guanidine, thiocarbanilide, hexamethylene tetramine, paraphenylene diamine, anhydroformaldehyde aniline, diphenyl guanidinephthalate, triphenyl guanidine, butylaldehyde aniline, dibutyl amine oleate, and dicyclohexylamine oleate may also be added.